Our objective is to define the effects of marihuana on the male reproductive system. The experiments will be conducted in male mice and will involve administration of purified constituents of marihuana: delta 9-tetrahydrocannabinol (THC) which is believed responsible for most of the behavioral effects of marihuana, and cannabinol (CBN) which is considered devoid of psychoactive action. The function of the pituitarygonadal axis in THC and CBN-treated animals will be evaluated from the following parameters: plasma LH and FSH levels, plasma testosterone level, concentration of LH receptor in the testis, production of testosterone by decapsulated testes in vitro, spermatogenesis, fertility and development of the progeny. Copulatory behavior, which has a demonstrated dependence on androgens will be examined in the same animals. In separate experiments, we will determine whether artificial maintenance of stable androgen levels in castrated animals prevents or modifies the behavioral effects of THC. In addition, we will examine testicular production of androgenic steroids after treatment with THC, CBN, other constituents of marihuana or metabolites of THC in vitro. We will also determine whether treatment of female mice with constituents of marihuana during pregnancy and lactation affects the development of male reproductive system and mating behavior in their progeny. The results will define the effects of marihuana on the development and function of the testis, suggest the mechanism of its action, and indicate whether changes in the endocrine function of the testes account for, or contribute to the behavioral effects of marihuana.